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41.
42.
Bertrand Schweitzer-Chaput Massaba Keita Thierry Milcent Sandrine Ongeri Benoit Crousse 《Tetrahedron》2012,68(35):7028-7034
A series of fluorinated N-aminoaziridines have been synthesized by the PhI(OAc)2-mediated aziridination procedure. The reaction was carried out with various protected hydrazides and fluorinated alkenes. The reaction was extended to alkenes bearing an amino acid and the ring opening of the CF3–N-aminoaziridines has been investigated. 相似文献
43.
Stanislas Larnier Jér?me Fehrenbach Mohamed Masmoudi 《Milan Journal of Mathematics》2012,80(2):411-441
The aim of this article is to review and extend the applications of the topological gradient to major image processing problems. We briefly review the topological gradient, and then present its application to the crack localization problem, which can be solved using the Dirichlet to Neumann approach. A very natural application of this technique in image processing is the inpainting problem, which can be solved by identifying the optimal location of the missing edges. Edge detection is of extreme importance, as edges convey essential information in a picture. A second natural application is then the image reconstruction. A class of image reconstruction problems is considered that includes restoration, demosaicing, segmentation and super-resolution. These problems are studied using a unified theoretical framework which is based on the topological gradient method. This tool is able to find the localization and orientation of the edges for blurred, low sampled, partially masked, noisy images. We review existing algorithms and propose new ones. The performance of our approach is compared with conventional image reconstruction processes. 相似文献
44.
Ren Milcent Go Barbier Batrice Yver Fathi Mazouz 《Journal of heterocyclic chemistry》1991,28(6):1511-1516
Some ethyl 5-aryl(or benzyl)-2-oxo-1,3,4-oxadiazole-3(2H)-acetates were prepared and treated with ammonia, primary amines or hydrazine to give 1-amino-2,4-imidazolidinedione or 1,3-diamino-2,4-imidazolidinedione derivatives. The 1,3-bis(benzylideneamino)-2,4-imidazolidinedione was obtained by reacting ethyl bromoacetate with the 1,5-dibenzylidenecarbonohydrazide sodium salt. 相似文献
45.
46.
Some 5-aryl(or benzyl)-2-oxo-1,3,4-oxadiazole-3(2H)-acetones or acetophenones 2 were easily prepared. These compounds reacted with hydrazine derivatives to give 4,5-dihydro-1,2,4-triazin-3(2H)-one derivatives 3 , 4 and 6 in good yields. With phenylhydrazine, the intermediate hydrazones 5 were obtained. Their conversion into triazinones necessitated the presence of sodium ethylate. 相似文献
47.
5-Aryl(or benzyl)-3-(2-bromoethyl)-1,3,4-oxadiazol-2(3H)-ones 3 have been prepared. They were reacted with secondary alkylamines without any change of the heterocycle to give amino derivatives 6 , but with primary alkylamines, cyclic transformation occurred to give 1-acylamino-3-alkylimidazolidin-2-ones 7 . In the presence of sodium alcoholate, bromo compounds 3 were transformed into 2-aryl(or benzyl)-4-alkoxycarbonyl-5,6-dihydro-4H-1,3,4-oxadiazines 9 . 相似文献
48.
Aromatic aldehyde aroylhydrazones when oxidizen with lead dioxide, in acetic acid, gave quickly the corresponding 1,2,4-oxadiazoles in good yields. Aromatic aldehyde carbodihydrazones on the other hand, gave derivatives of 4-amino-3-aryl-1m,2,4-triazol-5-ones, in dimethylformamide as solvent. To explane these results, some radical mechanisms are proposed. 相似文献
49.
Ren Milcent GO Barbier Sylvie Capelle Jean-Pierre Catteau 《Journal of heterocyclic chemistry》1994,31(2):319-324
Reactions of 2-chloroformylhydrazones of aromatic aldehydes or ketones 2 with various hydrazines were converted to monocarbonohydrazone derivatives 3 or 5 and/or tetrahydro-1,2,4,5-tetrazin-3(2H)-one derivatives 6 , 7 . By oxidation with lead dioxide, compounds 6 were transformed into stable 3,4-dihydro-3-oxo-1,2,4,5-tetrazin-1(2H)-yl radical derivatives 8 . 相似文献
50.
René Milcent Anna Akhnazarian Nathalie Lensen 《Journal of heterocyclic chemistry》1996,33(6):1829-1833
A series of ethyl 2-oxo-3(2H)-benzoxazoleacetate derivatives 2 have been synthesized. By reaction with ammonia, primary amines or hydrazine, these compounds 2 were transformed into 1-(2-hydroxyphenyl)-2,4-imidazolidinedione derivatives 4, 5 and 6 , respectively. Some of these new hydantoins 4 , treated with phosphorus oxychloride, gave 3H-2-oxoimidazo[2,1-b]benzoxazole derivatives 9 . Ethyl 2-oxo-3(2H)-benzoxazolepropionate ( 10 ) was prepared by a Michaël reaction of ethyl acrylate with 2-benzoxazolone ( 1a ). With 10 , no cyclic transformation was observed in the presence of ammonia or alkylamine. 相似文献